Assessment of Abnormalities in Reproductive Organs of Hot Pepper Induced by Low Night Temperature

Abstract

Low night temperature (LNT) adversely affects productivity of pepper (Capsicum annuum L.) grown in unheated greenhouses. Flower abnormalities were investigated in the local hot pepper cvs. Beldi and Baklouti grown in a growth chamber at a day/night temperature regime of low (25/10°C, LNT) or optimum night temperature (ONT; 25/20°C, as a control). The LNT induced abnormalities in pepper flowers but sensitivity was cultivar dependent; increased ovary diameter in ‘Baklouti’ (40% more than that in ‘Beldi’) was associated with a decrease in style length. Numbers of ovules decreased more than 60% under LNT (more so in ‘Baklouti’). In addition, longitudinal lengths and transverse diameters of ovaries, measured by transverse section, were affected by cultivar and temperature regime. Fruit set percentage was lowest and fruit characteristics were poorest when flowers were self-pollinated under LNT, although artificial pollination with pollen from ONT increased fruit set. More seed per fruit, and heavier and longer fruit, occurred when flowers were pollinated with pollen from ONT than when pollen from LNT was used. Where LNTs have negatively influenced yield, pepper growers need to consider alternative growth and production strategies to reduce damage to flowers.